I think it is Ironic how on history shows the Muslims cry about the Crusades. But forget how they over ran areas that had been Christian prior to the Muslim conquests such as Egypt, and the far eastern areas of the Roman Empire (Eastern Roman or Byzantine Empire), prior to the crusades.

It was alright for the Muslims to conquer those areas but not for the Christians to try and regain them?

It could be said that the original enemy of the U.S. Navy and Marines were the Muslim Barbary Pirates. The USN and USMC were eliminated after the Revolutionary War. They were reestablished largly to fight the Muslim Pirates of the Barbary Coast.